Rechargeable battery

ABSTRACT

In a rechargeable battery, a case is combined with an upper surface of a bare cell by being fixed to a lead plate electrically coupling a protection circuit board of a protection circuit module to the bare cell. Alternatively, the case is combined with the bare cell by being fixed to the protection circuit board so as not to be separated from the bare cell, thereby improving the reliability of the products.

CLAIM OF PRIORITY

This application makes reference to, incorporates the same herein, andclaims all benefits accruing under 35 U.S.C. §119 from an applicationearlier filed in the Korean Intellectual Property Office on the Nov. 7,2007, and there duly assigned Ser. No. 10-2007-0113061.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a rechargeable battery and, moreparticularly, to a rechargeable battery which can improve productivityby improving an assembly structure of the battery.

2. Related Art

Generally, a rechargeable battery is a battery which is rechargeable andis different from a disposable battery which is not rechargeable. Therechargeable battery has been widely used in the fields of electronicdevices, such as cellular phones, notebook computers and camcorders.Particularly, a lithium rechargeable battery has an operational voltageof 3.6V which is three times higher than that of an Ni—Cd battery or anNi—H battery, which are frequently used as power sources of electronicdevices, and which have high energy density per unit weight. As aresult, the lithium-ion battery has developed rapidly in recent years.

The lithium rechargeable battery includes a bare cell and a protectioncircuit module (PCM) for electrically protecting the operation of thebare cell. The bare cell comprises an electrode assembly including acathode plate, an anode plate and a separator interposed between them, acan receiving the electrode assembly and an electrolytic solution, and acap assembly sealing an opening part of the can.

Methods of fixing the protection circuit module to the bare cell includea molding method using injected melted resin and an assembling methodusing an injection molded case.

The method of fixing the protection circuit module to the bare cell bymolding melted resin has a problem in that the high temperature of themelted resin causes undesirable effects on various elements included inthe protection circuit module. Furthermore, it is difficult to form amolding resin at an exact position on one surface of the bare cell,thereby increasing defects.

Conversely, the method of fixing the protection circuit module to thebare cell by the injection molded case does not affect the elements ofthe protection circuit module by hot temperature, and since it is anassembling method using a case, it is always possible to assemble at anexact position of the bare cell. In addition, the assembling process issimple.

However, in the fixing method using the case, the case is fixed to thebare cell by a label sheet surrounding an outer circumference surface ofthe bare cell. In this regard, the case is fixed to the bare cell byadhesive force of the label sheet, which is a thin film, and thus thebinding force of the case attached to the bare cell is very weak.Accordingly, the case is easily twisted from an upper surface of thebare cell or, in an undesirable case, may be separated from the barecell.

As described above, the conventional case is easily separated from thebare cell because the case is fixed to the bare cell only by theadhesive force of the label sheet. Thus, there is a problem that thereliability of products is prominently damaged.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide arechargeable battery which can strongly fix a case to a bare cell so asnot to be separated from the bare cell.

Additional advantages, objects and features of the invention will be setforth, in part, in the following description, and will become apparent,in part, to those having ordinary skill in the art upon examination ofthe following or may be learned from practice of the invention.

According to an aspect of the present invention, a rechargeable batterycomprises: a bare cell; a protection circuit module including aprotection circuit board installed in the bare cell; a lead plateinstalled between the protection circuit board and the bare cell so asto electrically couple the protection circuit board and the bare cell;and a case connected to the bare cell so as to receive the protectioncircuit module on one surface of the bare cell; wherein at least oneprojection is formed on the lead plate and a projection fixing partcombined with the projection is formed at the case so as to combine thecase with the bare cell.

The lead plate may be installed on both ends of an upper surface of acap plate of the bare cell, and includes a substrate fixing part weldedto the protection circuit board and a bare cell fixing part welded tothe bare cell, and the projection may be formed horizontally andoutwardly from a side surface of the bare cell fixing part.

The lead plate may be fixed by laser-welding the bare cell fixing partto the upper surface of the cap plate.

The projection fixing part of the case may be formed in the shape of ahole or a groove.

The case may include a sleeve covering an outer circumferential surfaceof an upper periphery of the bare cell, the sleeve being extended at itslower end part, and the projection fixing part may be formed on thesleeve.

A label sheet may be attached to a side surface of the bare cell so asto cover the sleeve of the case.

According to another aspect of the present invention, a rechargeablebattery comprises: a bare cell; a protection circuit module including aprotection circuit board installed in the bare cell; and an upper caseconnected to the bare cell while receiving the protection circuit moduleon one surface of the bare cell; wherein at least one projection isformed on the protection circuit board, and a projection fixing partcombined with the projection is formed at the case so as to hold thecase by means of the bare cell.

The projection of the protection circuit board is projected horizontallyand outwardly from a side surface of the protection circuit board.

The projection fixing part of the upper case may be formed in the shapeof a hole or a groove.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention, and many of the attendantadvantages thereof, will be readily apparent as the same becomes betterunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings in which likereference symbols indicated the same or similar components, wherein:

FIG. 1 is an exploded perspective view of a rechargeable batteryaccording to a first exemplary embodiment of the present invention;

FIG. 2 is a perspective view of a state wherein an upper case of therechargeable battery according to the first exemplary embodiment of thepresent invention is combined;

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is a perspective view of a state wherein a label sheet accordingto the first exemplary embodiment is attached;

FIG. 5 is a sectional view taken along line V-V of FIG. 4;

FIG. 6 is a sectional view of the upper case of the rechargeable batteryaccording to a second exemplary embodiment of the present invention;

FIG. 7 is an exploded perspective view of a bare cell and the upper caseaccording to a third exemplary embodiment of the present invention;

FIG. 8 is a sectional view of a state wherein a label sheet according tothe third exemplary embodiment is attached; and

FIG. 9 is a sectional view of an upper case according to a fourthexemplary embodiment.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, preferred embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings. Theaspects and features of the present invention and methods for achievingthe aspects and features will be apparent by referring to theembodiments to be described in detail with reference to the accompanyingdrawings. However, the present invention is not limited to theembodiments disclosed hereinafter, but can be implemented in diverseforms. The matters defined in the description, such as the detailedconstruction and elements, are nothing but specific details provided toassist those of ordinary skill in the art in a comprehensiveunderstanding of the invention, and the present invention is onlydefined within the scope of the appended claims. In the entiredescription of the present invention, the same drawing referencenumerals are used for the same elements across various figures.

FIG. 1 is an exploded perspective view of a rechargeable batteryaccording to a first exemplary embodiment of the present invention, FIG.2 is a perspective view of a state wherein an upper case of therechargeable battery according to the first exemplary embodiment of thepresent invention is combined, FIG. 3 is a sectional view taken alongline III-III of FIG. 2, FIG. 4 is a perspective view of a state whereina label sheet according to the first exemplary embodiment is attached,and FIG. 5 is a sectional view taken along line V-V of FIG. 4.

Referring to FIGS. 1 thru 5, the rechargeable battery includes a barecell 100, a protection circuit module 200 arranged on one surface of thebare cell 100, and an upper case 400 covering the protection circuitmodule 200. The protection circuit module 200 further includes aprotection circuit board 210, and the bare cell 100 and the protectioncircuit module 200 are electrically coupled to each other by lead plates310 and 320.

The upper case 400 is fixed by the lead plates 310 and 320 so as to becombined with the bare cell 100.

A lower case 500 is installed on a lower surface of the bare cell 100,and a label sheet 600 is wound and attached on a side surface of thebare cell 100.

The bare cell 100 includes an electrode assembly (not shown) comprisinga cathode plate, an anode plate and a separator, a can 110 receiving theelectrode assembly and an electrolytic solution, a cap assembly (notshown) including a cap plate 120 for sealing an opening part of the can110, and an electrode terminal 130 passing through the cap plate 120 soas to connect the electrode terminal 130 to an electrical terminal (notshown) of the protection circuit board 210.

The protection circuit module 200 is composed of various electronicdevices (not shown) installed on the protection circuit board 210. Athrough-hole 211 is formed in a middle part of the protection circuitboard 210, and an electrical terminal connected to the electrodeterminal 130 is horizontally installed in parallel with the cap plate120 and through the through-hole 211.

The lead plates 310 and 320 are installed on respective ends of theupper surface of the cap plate 120. The lead plates 310 and 320 arewelded to the protection circuit board 210 and cap plate 120 so as toelectrically couple them to each other. Substrate fixing parts 312 and322 of the lead plates 310 and 320, respectively, are welded to theprotection circuit board 210, and bare cell fixing parts 314 and 324 arewelded to the bare cell 100. The substrate fixing parts 312 and 322 areformed by bending upper parts of the lead plates 310 and 320,respectively, and the bare cell fixing parts 314 and 324 are formed bybending lower parts of the lead plates 310 and 320, respectively. Thelead plate 310 and 320 are fixed by laser-welding the bare cell fixingpart 312 and 322, respectively, to the upper surface of the cap plate120.

The electrode terminal 130 of the bare cell 100 is electrically coupledto the electrical terminal 220 of the protection circuit board 210.Furthermore, another electrical terminal (not shown) of the protectioncircuit board 210 is connected to the bare cell by the lead plates 310and 320. In this regard, when the electrode terminal 130 of the barecell 100 is connected to the electrical terminal 220 with negativepolarity, another electrical terminal of the protection circuit board210 has positive polarity.

The upper case 400 is combined with the upper part of the bare cell 100so as to receive the protection circuit board 210. At this point, theupper case 400 is fixed by the lead plates 310 and 320.

The upper case 400 is fixed by projections 316, 318, 326 and 328 formedon the lead plates 310 and 320, respectively, and projection fixingholes 432,434,436 and 438 formed on the upper case 400.

The projections 316, 318, 326 and 328 are horizontally projected fromboth side surfaces of the bare cell fixing parts 314 and 324 of the leadplates 310 and 320. However, the projections 316, 318, 326 and 328 maybe formed on at least one side surface of the bare cell fixing parts 314and 324. In the case where the projections are formed on any one sidesurface, it is desirable that when the projection 316 is formed on oneside surface of one lead plate 310, the projection 328 be formed on theopposite side surface of the other lead plate 320. This is the reasonthat it is desirable to fix the upper case 400 by forces simultaneouslyacting in directions facing each other.

The projection fixing holes 432, 434, 436 and 438 are formed on an upperend of the sleeve 410 of the upper case 400 so as to pass through thesleeve 410.

Thus, when the upper case 400 is combined with the upper part of thebare cell 100, the projections 316, 318, 326 and 328 are inserted intothe projection fixing holes 432, 434, 436 and 438, respectively, of theupper case 400. Accordingly, the upper case 400 is fixed by the leadplates 310 and 320.

When the upper case 400 is fixed by the lead plates 310 and 320, a labelsheet 600 surrounding the side surface of the bare cell 100 is attached.The label sheet 600 is attached so as to cover the sleeve 410 extendedat both lower ends of the upper case 400. Accordingly, the label sheet600 is attached so as to cover the projection fixing holes 432, 434, 436and 438, thereby preventing the projection fixing holes 432, 434, 436and 438 from being exposed to the outside.

On the other hand, lower case 500 may be attached to the lower surfaceof the bare cell 100 by adhesive or the like. The lower case 500 iscombined with a lower surface of the can 110 so as to protect the barecell 100 from external impacts.

FIG. 6 is a sectional view of the upper case according to a secondexemplary embodiment of the present invention.

Referring to FIG. 6, projection fixing parts may be formed in the shapeof a groove on the upper case. That is, projection fixing grooves 432 aand 434 a are formed inside the upper case 400A and thus, projectionscan be inserted into the upper case 100A and fixed by the projectionfixing grooves 432 a and 434 a.

When the projection fixing parts are formed in the shape of groove, itis possible to cover the projections 316, 318, 326 and 328 formed on thelead plates 310 and 320 so as not to be exposed to the outside.Accordingly, even if the label sheet 600 is not attached, the appearanceof the rechargeable battery becomes good because the projections 316,318, 326 and 328 are not exposed to the outside.

FIG. 7 is an exploded perspective view of a bare cell and the upper caseaccording to a third exemplary embodiment of the present invention, andFIG. 8 is a sectional view of a state wherein a label sheet according tothe third exemplary embodiment is attached.

In the third embodiment, the same drawing reference numerals are usedfor the same elements.

Referring to FIGS.7 and 8, in the rechargeable battery, projections forholding by fixing an upper case 400B to a bare cell 100 are formed on aprotection circuit board 210A.

Projections 212,214,216 and 218 are respectively formed on both sidesurfaces of front and rear parts of the protection circuit board 210Aoutwardly and horizontally. Furthermore, projection fixing holes 442,444, 446 and 448 are respectively formed at positions of the upper case400B corresponding to the projections 212, 214,216 and 218 of theprotection circuit board.

In the rechargeable battery constituted as described above, in theprocess wherein the upper case 400B is assembled on the upper part ofthe bare cell 100, the projections 212,214,216 and 218 of the protectioncircuit board 210A are inserted into the projection fixing holes442,444, 446 and 448 of the case 400B. Thus, the case 400B is fixed tothe protection circuit board 210A so as not to be separated from theupper part of the bare cell 100.

After the upper case 400B is assembled, a label sheet 600 may beattached on an outer surface of the bare cell 100. The label sheet 600is attached so as to cover a sleeve 410 extended at left and rightperipheral sides of a lower end of the case 400B, thereby providing abinding force to maintain the upper case 400B fixed to the bare cell100.

FIG. 9 is a sectional view of the upper case according to a fourthexemplary embodiment.

Referring to FIG. 9, the projection fixing part of the upper case may beformed in the shape of a groove. That is, projection fixing grooves 442a and 444 a are formed inside an upper case 400C, and thus projectionscan be inserted into and fixed by the projection fixing grooves 442 aand 444 a.

When the projection fixing parts are formed in the shape of groove asdescribed above, the projections 212, 214, 216 and 218 formed on theprotection circuit board 210A are not exposed to the outside of theupper case 400C. Accordingly, the appearance of the rechargeable batterybecomes good.

As described above, the rechargeable battery according to the presentinvention produces the following effects.

First, the case is stably fixed to the bare cell so as not to beseparated from the bare cell, thereby improving reliability of products.

Second, the case is fixed by the projection formed on the lead plate,thereby improving the binding force of the case to the bare cell.

Third, the projections are inserted into the projection fixing groovesso as not to be exposed to the outside of the case, thereby allowing theappearance to be good.

Fourth, the case is fixed by a projection formed on the protectioncircuit board, thereby improving the binding force which binds the caseto the bare cell.

It should be understood by those of ordinary skill in the art thatvarious replacements, modifications and changes in the form and detailmay be made therein without departing from the spirit and scope of thepresent invention as defined by the following claims. Therefore, it isto be appreciated that the above described embodiments are for purposesof illustration only and are not to be construed as limitations of theinvention.

1. A rechargeable battery, comprising: a bare cell; a protection circuitmodule including a protection circuit board installed in the bare cell;a lead plate installed between the protection circuit board and the barecell so as to electrically couple the protection circuit board and barecell; and a case connected to the bare cell so as to receive theprotection circuit module on a surface of the bare cell; wherein atleast one projection is formed on the lead plate, and a projectionfixing part combined with the projection is formed at the case so as tocombine the case with the bare cell.
 2. The rechargeable battery ofclaim 1, wherein the lead plate is installed on both ends of an uppersurface of a cap plate of the bare cell and includes a substrate fixingpart welded to the protection circuit board and a bare cell fixing partwelded to the bare cell, and wherein the projection is formedhorizontally and outwardly from a side surface of the bare cell fixingpart.
 3. The rechargeable battery of claim 2, wherein the lead plate isfixed by laser-welding the bare cell fixing part to the upper surface ofthe cap plate.
 4. The rechargeable battery of claim 1, wherein theprojection fixing part of the case is formed in a shape of a hole. 5.The rechargeable battery of claim 1, wherein the projection fixing partof the case is formed in a shape of a groove.
 6. The rechargeablebattery of claim 1, wherein the case comprises a sleeve covering anouter circumferential surface of an upper periphery of the bare cell andbeing extended at its lower end part, and the projection fixing part isformed on the sleeve.
 7. The rechargeable battery of claim 6, wherein alabel sheet is attached to a side surface of the bare cell so as tocover the sleeve of the case.
 8. A rechargeable battery, comprising: abare cell; a protection circuit module including a protection circuitboard installed in the bare cell; and an upper case connected to thebare cell while receiving the protection circuit module on one surfaceof the bare cell; wherein at least one projection is formed on theprotection circuit board, and a projection fixing part combined with theprojection is formed at the case so as to combine the case with the barecell.
 9. The rechargeable battery of claim 8, wherein said at least oneprojection of the protection circuit board is projected horizontally andoutwardly from a side surface of the protection circuit board.
 10. Therechargeable battery of claim 8, wherein the projection fixing part isformed in a shape of a hole.
 11. The rechargeable battery of claim 8,wherein the projection fixing part is formed in a shape of a groove.